Electron beam processing of LDPE/EVA/PCR ternary blends: radiation sensitivity evaluation and physico-mechanical characterization

LDPE/EVA/PCR blends having fixed percentage of PCR were prepared by melt mixing and irradiated to different radiation doses using electron beam. Gel fraction and crosslinking density of the blends were found to increase with increase in EVA content in the formulation, suggesting higher radiation sensitivity of EVA. The heat of mixing and polymer-polymer interaction parameter indicated better miscibility between EVA/PCR than between LDPE/PCR and LDPE/EVA. Dynamic mechanical properties of the blends were found to significantly vary with the variation in the EVA fraction in the blends. In the composition range studied the storage modulus decreased from 3.8 x 10(8) to similar to 1 x 10(8) Pa at strain amplitude of 5 x 10(-6) m. The experimentally obtained data deviated significantly from both the series as well as parallel model. The bulk density showed a positive deviation from additive rule. The X-ray diffraction pattern of the blends revealed reduction in the crystallinity of LDPE on blend formation. DSC thermograms of blends did not indicate any significant shift in the melting peaks, indicating immiscibility of LDPE and EVA domains in the presence of PCR.